Combination of interferon-beta and angiotensin-converting enzyme inhibitor, perindopril, attenuates the murine liver fibrosis development

Effects of high salt intake on glucose metabolism, liver function, and the microbiome in rats: influence of ACE inhibitors and angiotensin II receptor blockers

High-salt diets (HSDs) are known to impact blood pressure and cardiovascular health, but their effects on glucose metabolism, liver function, and gut microbiota remain poorly understood. This study investigates how long-term HSD affects these physiological processes and evaluates the potential therapeutic effects of ACE inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs). Male Sprague-Dawley rats were fed a normal salt diet (0.3% NaCl), a moderate salt diet (2% NaCl), or a high-salt diet (8% NaCl) for 12 wk. Two subgroups in the HSD condition received telmisartan or enalapril. We assessed blood pressure, glucose homeostasis, liver inflammation, pancreatic function, and gut microbiota composition. HSD rats exhibited significantly higher blood pressure [130 ± 2 mmHg in normal diet (ND) vs. 144 ± 4 mmHg in HSD; P < 0.01], reduced fasting insulin (1.33 ± 0.14 ng/mL in ND vs. 0.60 ± 0.05 ng/mL in HSD; P < 0.01), and gut microbiota dysbiosis, with a 71% reduction in Ruminococcus species (P = 0.018). Liver inflammation, indicated by an increase in CD68+ macrophages, was also observed in the HSD group. Telmisartan treatment significantly reduced liver inflammation but did not fully restore metabolic homeostasis. HSD disrupts multiple physiological systems, including glucose metabolism and liver function, partly through gut microbiota alterations. ACEIs and ARBs provided partial protection, highlighting the need for multitargeted interventions to mitigate high-salt diet effects.NEW & NOTEWORTHY High-salt diet induces multisystem disruptions, including liver inflammation, reduced insulin levels, and gut microbiota imbalance. ACEIs and ARBs showed limited efficacy, highlighting the need for comprehensive therapeutic approaches.

Is serum angiotensin converting enzyme level a useful non-invasive marker for liver fibrosis in patients with chronic hepatitis C?

OBJECTIVE

Chronic hepatitis C (CHC) continues to be a critical problem. The liver fibrosis score is the most valuable tool in determining treatment and prognosis. Liver biopsy is still considered a gold method but, due to unmet needs, new non-invasive markers are required. The aim of this study was to investigate any possible relationship between serum angiotensin-converting enzyme (ACE) levels and the stages of liver fibrosis in patients with CHC.

METHOD

A total 100 CHC and 100 healthy subjects were enrolled in this study. The relationship between serum ACE level and the stages liver fibrosis was investigated using three different formats, as follows: (group [G]-I, classic Ishak's Score from F1 to F6; G-II, mild [F1-2], moderate [F3-4] and severe [F5-6]; G-III, mild [≤ F2] and advanced [F > 2]). The clinical usability of serum ACE level for both groups was also investigated.

RESULTS

Median serum ACE levels were higher in the healthy group than in CHC (42.5 [7-119] vs. 36 [7-91] U/I, p=0.002). There was no statistical difference among the three different fibrosis groups (G-I, G-II, G-III, p=0.797, p=0.986, and p=0.874) and no correlation between serum ACE level and the stages of liver fibrosis (r=0.026, p=0.923). The usability of serum ACE for evaluated patients with CHC and healthy subjects were calculated as 47% and 64%, respectively.

CONCLUSION

Our study indicated that there is no relationship or correlation between serum ACE levels and stages of liver fibrosis in patients with CHC. The assessment of serum ACE level using genetically corrected reference values may provide more accurate results.

Modulation of angiotensin II signaling in the prevention of fibrosis

Over the last decade, it has become clear that the role of angiotensin II extends far beyond recognized renal and cardiovascular effects. The presence of an autologous renin-angiotensin system has been demonstrated in almost all tissues of the body. It is now known that angiotensin II acts both independently and in synergy with TGF-beta to induce fibrosis via the angiotensin type 1 receptor (AT1) in a multitude of tissues outside of the cardiovascular and renal systems, including pulmonary fibrosis, intra-abdominal fibrosis, and systemic sclerosis. Interestingly, recent studies have described a paradoxically regenerative effect of the angiotensin system via stimulation of the angiotensin type 2 receptor (AT2). Activation of AT2 has been shown to ameliorate fibrosis in animal models of skeletal muscle, gastrointestinal, and neurologic diseases. Clinical reports suggest a beneficial role for modulation of angiotensin II signaling in cutaneous scarring. This article reviews current knowledge on the role that angiotensin II plays in tissue fibrosis, as well as current and potential therapies targeting this system.

The effect of antifibrotic drugs in rat precision-cut fibrotic liver slices

Two important signaling pathways in liver fibrosis are the PDGF- and TGFβ pathway and compounds inhibiting these pathways are currently developed as antifibrotic drugs. Testing antifibrotic drugs requires large numbers of animal experiments with high discomfort. Therefore, a method to study these drugs ex vivo was developed using precision-cut liver slices from fibrotic rat livers (fPCLS), representing an ex vivo model with a multicellular fibrotic environment. We characterized the fibrotic process in fPCLS from rat livers after 3 weeks of bile duct ligation (BDL) during incubation and tested compounds predominantly inhibiting the TGFβ pathway (perindopril, valproic acid, rosmarinic acid, tetrandrine and pirfenidone) and PDGF pathway (imatinib, sorafenib and sunitinib). Gene expression of heat shock protein 47 (Hsp47), α smooth muscle actin (αSma) and pro-collagen 1A1 (Pcol1A1) and protein expression of collagens were determined. During 48 hours of incubation, the fibrosis process continued in control fPCLS as judged by the increased gene expression of the three fibrosis markers, and the protein expression of collagen 1, mature fibrillar collagen and total collagen. Most PDGF-inhibitors and TGFβ-inhibitors significantly inhibited the increase in gene expression of Hsp47, αSma and Pcol1A1. Protein expression of collagen 1 was significantly reduced by all PDGF-inhibitors and TGFβ-inhibitors, while total collagen was decreased by rosmarinic acid and tetrandrine only. However, fibrillar collagen expression was not changed by any of the drugs. In conclusion, rat fPCLS can be used as a functional ex vivo model of established liver fibrosis to test antifibrotic compounds inhibiting the PDGF- and TGFβ signalling pathway.

Precision-cut liver slices as a model for the early onset of liver fibrosis to test antifibrotic drugs

Induction of fibrosis during prolonged culture of precision-cut liver slices (PCLS) was reported. In this study, the use of rat PCLS was investigated to further characterize the mechanism of early onset of fibrosis in this model and the effects of antifibrotic compounds. Rat PCLS were incubated for 48h, viability was assessed by ATP and gene expression of PDGF-B and TGF-β1 and the fibrosis markers Hsp47, αSma and Pcol1A1 and collagen1 protein expressions were determined. The effects of the antifibrotic drugs imatinib, sorafenib and sunitinib, PDGF-pathway inhibitors, and perindopril, valproic acid, rosmarinic acid, tetrandrine and pirfenidone, TGFβ-pathway inhibitors, were determined. After 48h of incubation, viability of the PCLS was maintained and gene expression of PDGF-B was increased while TGF-β1 was not changed. Hsp47, αSma and Pcol1A1 gene expressions were significantly elevated in PCLS after 48h, which was further increased by PDGF-BB and TGF-β1. The increased gene expression of fibrosis markers was inhibited by all three PDGF-inhibitors, while TGFβ-inhibitors showed marginal effects. The protein expression of collagen 1 was inhibited by imatinib, perindopril, tetrandrine and pirfenidone. In conclusion, the increased gene expression of PDGF-B and the down-regulation of fibrosis markers by PDGF-pathway inhibitors, together with the absence of elevated TGF-β1 gene expression and the limited effect of the TGFβ-pathway inhibitors, indicated the predominance of the PDGF pathway in the early onset of fibrosis in PCLS. PCLS appear a useful model for research of the early onset of fibrosis and for testing of antifibrotic drugs acting on the PDGF pathway.

Selective antitumor effect of neural stem cells expressing cytosine deaminase and interferon-beta against ductal breast cancer cells in cellular and xenograft models

Due to their inherent tumor-tropic properties, genetically engineered stem cells may be advantageous for gene therapy treatment of various human cancers, including brain, liver, ovarian, and prostate malignancies. In this study, we employed human neural stem cells (HB1.F3; hNSCs) transduced with genes expressing Escherichia coli cytosine deaminase (HB1.F3.CD) and human interferon-beta (HB1.F3.CD.IFN-β) as a treatment strategy for ductal breast cancer. CD can convert the prodrug 5-fluorocytosine (5-FC) to its active chemotherapeutic form, 5-fluorouracil (5-FU), which induces a tumor-killing effect through DNA synthesis inhibition. IFN-β also strongly inhibits tumor growth by the apoptotic process. RT-PCR confirmed that HB1.F3.CD cells expressed CD and HB1.F3.CD.IFN-β cells expressed both CD and IFN-β. A modified transwell migration assay showed that HB1.F3.CD and HB1.F3.CD.IFN-β cells selectively migrated toward MCF-7 and MDA-MB-231 human breast cancer cells. In hNSC-breast cancer co-cultures the viability of breast cancer cells which were significantly reduced by HB1.F3.CD or HB1.F3.CD.IFN-β cells in the presence of 5-FC. The tumor inhibitory effect was greater with the HB1.F3.CD.IFN-β cells, indicating an additional effect of IFN-β to 5-FU. In addition, the tumor-tropic properties of these hNSCs were found to be attributed to chemoattractant molecules secreted by breast cancer cells, including stem cell factor (SCF), c-kit, vascular endothelial growth factor (VEGF), and VEGF receptor 2. An in vivo assay performed using MDA-MB-231/luc breast cancer mammary fat pad xenografts in immunodeficient mice resulted in 50% reduced tumor growth and increased long-term survival in HB1.F3.CD and HB1.F3.CD.IFN-β plus 5-FC treated mice relative to controls. Our results suggest that hNSCs genetically modified to express CD and/or IFN-β genes can be used as a novel targeted cancer gene therapy.

Angiotensin converting enzyme inhibitors and hepatocellular carcinoma incidence in the General Practice Research Database

OBJECTIVE

Laboratory findings demonstrate anticancer effects of angiotensin converting enzyme (ACE) inhibitors, including anti-angiogenic activity and inhibition of liver cancer growth in rodent models. Small studies in humans indicate potential for therapeutic anticancer effects and warrant further larger studies.

METHODS

A case-control study using the General Practice Research Database examined whether prior ACE inhibitor usage was associated with a reduction in incidence of hepatocellular carcinoma (HCC).

RESULTS

Two hundred twenty-four HCC cases were identified, each matched to up to 10 controls by age, sex, and general practice. The data show that HCC is associated with a small, nonsignificant increase in prior use of ACE inhibitors (OR = 1.16, CI = 0.67-2.00). ACE inhibitor use was 7.1% (of 224) in cases and 5.9% (of 2,313) in controls. No significant effects were found when investigating the effect of dose and exposure duration.

CONCLUSIONS

We found no clear protective effect of ever or long term use of ACE inhibitors against the development of HCC. Our study suggests that it is unlikely that this class of drugs will be a clinically useful cancer chemoprevention therapy.

Combination treatment of angiotensin II type I receptor blocker and new oral iron chelator attenuates progression of nonalcoholic steatohepatitis in rats

Angiotensin II type I receptor blocker and iron chelator reportedly exert suppressive effects on nonalcoholic steatohepatitis (NASH) progression, including liver fibrosis and hepatocarcinogenesis. The aim of this study was to elucidate the combined effect of losartan (LOS), an angiotensin II type I receptor blocker, and deferasirox (DSX), a newly developed oral iron chelator, on the progression of NASH in rats. To induce NASH, F344 rats were fed a choline-deficient l-amino acid-defined diet for 12 wk, and the effects of LOS and DSX at clinically comparable low doses were elucidated in conjunction with oxidative stress, neovascularization, and hepatic stellate cells (HSC) activation, all known to play important roles in the progression of NASH. Treatment with both LOS and DSX suppressed choline-deficient L-amino acid-defined diet-induced liver fibrosis development and hepatocarcinogenesis. This combination treatment exerted a stronger inhibitory effect compared with treatment with a single agent. These inhibitory effects occurred almost concurrently with the suppression of oxidative stress, neovascularization, and HSC activation. Our in vitro study demonstrated that LOS and DSX inhibited angiotensin II-induced proliferation, transforming growth factor-β(1) expression of activated HSC, and in vitro angiogenesis. These results indicated that dual inhibition by combined treatment of LOS and DSX attenuated the progression of NASH. Since both agents are widely used in clinical practice, this combination therapy may represent a potential new strategy against NASH in the near future.

Mesenchymal Stem Cells Overexpressing IFN-β Inhibit Breast Cancer Growth and Metastases through Stat3 Signaling in a Syngeneic Tumor Model

We previously demonstrated that mesenchymal stem/stromal cells (MSC) are recruited to tumors and that IFN-β produced by MSC inhibited tumor growth in xenograft models. Because of a deficient immune system, murine xenograft models cannot fully recapitulate tumor and immune cell interactions during progression. Therefore we investigated the capacity of MSC to migrate to and engraft into primary breast tumor sites and subsequently explore mechanisms of tumor inhibition by MSC-delivered IFN-β in a syngeneic, immunocompetent murine model. Herein we report that 1) systemically administrated MSC migrate to established 4 T1 breast cancer sites and localize among the tumor-stroma border and throughout the tumor mass; 2) high levels of IFN-β secreted by MSC are detectable in the tumor microenvironment but not in circulation; 3) intratumorally produced IFN-β inactivates constitutive phosphorylation of signal transducer activator transcription factor 3 (Stat3), Src, and Akt and down-regulates cMyc and MMP2 expression in 4 T1 cells, and 4) in mice with established breast cancer IFN-β expressing MSC administered systemically resulted in inhibition of primary cancer growth and in dramatic reduction of pulmonary and hepatic metastases. 5) MSC-IFN-β treated, but not control mice, maintained normal levels of splenic mature dendritic (DC), CD8+ T cells and CD4+/Foxp3+ regulatory T-cells (Treg). Our findings suggest that MSC are capable of migrating to tumor sites in an immunocompetent environment, that IFN-β produced by MSC suppresses breast cancer growth through inhibition of Stat3 signaling, and dramatically reduces pulmonary and hepatic metastases.

ELECTRONIC SUPPLEMENTARY MATERIAL

The online version of this article (doi:10.1007/s12307-010-0041-8) contains supplementary material, which is available to authorized users.

The effect of angiotensin-blocking agents on liver fibrosis in patients with hepatitis C

BACKGROUND

Multiple studies implicate the renin-angiotensin system in hepatic fibrogenesis. Few studies have examined the effects of angiotensin blockade on liver fibrosis via human histology.

AIMS

We studied the histological effect of angiotensin II blocking agents in chronic hepatitis C patients.

METHODS

This was a retrospective study of 284 chronic hepatitis C patients from 2001 to 2006 who underwent a liver biopsy. Group I was comprised of 143 hypertensive patients who received angiotensin-blocking agents. Group II was comprised of 91 hypertensive subjects who received hypertensive agents other than angiotensin blockers. Group III was comprised of 50 non-hypertensive subjects.

RESULTS

The groups were similar in age, sex, hepatitis C genotype, viral load and disease duration. They varied significantly in total diabetic patients (Group I, 43; Group II, 10; Group III, 1; P=0.0001), consistent with recommended use of angiotensin-converting enzyme inhibitors in hypertensive diabetics. Non-hypertensive patients had significantly less fibrosis than hypertensive patients, regardless of antihypertensive medications (Group I, 3.20; Group II, 3.73; Group III, 2.5; P=0.0002). Group I had significantly less fibrosis than Group II (P=0.02). This finding persisted in a non-diabetic subgroup of Groups I and II (Group I, 3.07; Group II, 3.69; P=0.0129).

CONCLUSION

Patients with hepatitis C and hypertension have increased fibrosis compared with non-hypertensive patients. Hypertensive patients receiving angiotensin-blocking agents had less fibrosis than hypertensive patients who did not receive angiotensin-blocking agents. This suggests an association with hypertension, possibly via the renin-angiotensin system in the fibrosis development and suggests a beneficial role of angiotensin II blockade in hepatitis C virus-related fibrosis.

Prevention and treatment of hepatic cirrhosis with herbal medicine Hongtian Gankang

AIM: To investigate the mechanism underlying preventing and treating hepatic cirrhosis with Hong Tian Gan Kang (HTGK) in mice.

METHODS: Sixty mice were divided randomly into 4 groups: normal control group, model control group, prevention group and treatment group. Except the mice in normal control group, all mice were given injection of CCl₄ into abdominal cavity that had been proved to induce experimental hepatic cirrhosis. In prevention group, mice were also given HTGK simultaneously by intragastric administration for 180 days, whereas mice in treatment group were given HTGK 150 days after modeling. Liver tissue and spleen tissue were made into sections stained with HE to evaluate the extent of liver cirrhosis and morphologic changes and to detect the expression of TGF-β1, IFN-γ, IgG, CD3 using immunohistochemistry.

RESULTS: Expression level of TGF-β1 in liver and spleen was markedly higher in model group than in control, prevention and treatment groups (F = 80.155, 120.850, both P < 0.05). The expression of IFN-γ and IgG was most obvious in treatment group, second in prevention group and least in model group (F = 53.584, 118.240, 85.075, 105.566, all P < 0.05). Compared with model group, expression levels of CD3 in prevention and treatment groups were significantly increased (F = 42.969, 69.775, both P < 0.05).

CONCLUSION: HTGK can improve the function of immune system so that it can prevent and cure hepatic cirrhosis effectively.

Cytokines and renin-angiotensin system signaling in hepatic fibrosis

Hepatic fibrosis is the result of a complex interplay between resident hepatic cells, infiltrating inflammatory cells, and a number of locally acting peptides called cytokines. Key mediators include transforming growth factor b1, vasoactive substances, adipokines, inflammatory cytokines and chemokines. Angiotensin II, the main effector of the renin-angiotensin system, is a true cytokine that plays a major role in liver fibrosis. Angiotensin II is locally synthesized in the injured liver and induces profibrogenic actions in hepatic stellate cells. Drugs blocking the renin-angiotensin system are promising antifibrotic agents. There are multiple signal transduction pathways involved in cytokine signaling. Drugs interfering intracellular pathways involved in increased collagen production are potential therapies for liver fibrosis.

Gene modulation for treating liver fibrosis

Despite tremendous progress in our understanding of fibrogenesis, injury stimuli process, inflammation, and hepatic stellate cell (HSC) activation, there is still no standard treatment for liver fibrosis. Delivery of small molecular weight drugs, proteins, and nucleic acids to specific liver cell types remains a challenge due to the overexpression of extracellular matrix (ECM) and consequent closure of sinusoidal gaps. In addition, activation of HSCs and subsequent release of inflammatory cytokines and infiltration of immune cells are other major obstacles to the treatment of liver fibrosis. To overcome these barriers, different therapeutic approaches are being investigated. Among them, the modulation of certain aberrant protein production is quite promising for treating liver fibrosis. In this review, we describe the mechanism of antisense, antigene, and RNA interference (RNAi) therapies and discuss how the backbone modification of oligonucleotides affects their in vivo stability, biodistribution, and bioactivity. Strategies for delivering these nucleic acids to specific cell types are discussed. This review critically addresses various insights developed with each individual strategy and for multipronged approaches, which will be helpful in achieving more effective outcomes.

Blockade of renin-angiotensin system in antifibrotic therapy

Recent studies have shown that the renin-angiotensin system (RAS) plays a pivotal role in liver fibrosis. An intrahepatic RAS is expressed in chronically damaged livers, and angiotensin-II (AT-II) reportedly stimulates contraction and proliferation of the activated hepatic stellate cells (Ac-HSC), and increases the transforming growth factor-beta (TGF-beta) expression through angiotensin type-I receptors (AT1-R). Some studies have demonstrated that the clinically used angiotensin-converting enzyme (ACE) inhibitor (ACE-I), and AT1-R blockers (ARB) significantly attenuated experimental liver fibrosis along with suppression of the Ac-HSC and hepatic TGF-beta expression. Angiotensin-II also stimulates the tissue inhibitor of metalloproteinases-1 (TIMP-1) in a dose- and time-dependent manner via protein kinase-C as an intracellular signaling cascade in the Ac-HSC, and these effects are completely suppressed by ARB. Combination treatment with low-dose interferon (IFN) and ACE-I exerts a stronger inhibitory effect than either single agent on its own. In humans it has been reported that ARB markedly improved the liver fibrosis score and TGF-beta expression in patients with chronic hepatitis C and non-alcoholic steatohepatitis. Serum fibrosis markers also significantly improved by treatment with low-dose IFN and ACE-I in patients with chronic hepatitis C, refractory to IFN monotherapy. Collectively, these data suggest that the interaction between AT-II and AT1-R plays a pivotal role in liver fibrosis development. Because both ACE-I and ARB are widely used in clinical practice without serious side-effects, these drugs in combination with IFN may provide a new strategy for antifibrosis therapy.

Interferon augments the anti-fibrotic activity of an angiotensin-converting enzyme inhibitor in patients with refractory chronic hepatitis C

AIM: To evaluate the effect of combination treatment with the interferon (IFN) and angiotensin-converting enzyme inhibitor (ACE-I) on several fibrotic indices in patients with refractory chronic hepatitis C (CHC).

METHODS: Perindopril (an ACE-I; 4 mg/d) and/or natural IFN (3 MU/L; 3 times a week) were administered for 12 mo to refractory CHC patients, and several indices of serum fibrosis markers were analyzed.

RESULTS: ACE-Idecreased the serum fibrosis markers, whereas single treatment with IFN did not exert these inhibitory effects. However, IFN significantly augmented the effects of ACE-I, and the combination treatment exerted the most potent inhibitory effects. The serum levels of alanine transaminase and HCV-RNA were not significantly different between the groups, whereas the plasma level of transforming growth factor-β was significantly attenuated almost in parallel with suppression of the serum fibrosis markers.

CONCLUSION: The combination therapy of an ACE-Iand IFN may have a diverse effect on disease progression in patients with CHC refractory to IFN therapy through its anti-fibrotic effect.

Angiotensin II and Aldosterone stimulating NF-kappaB and AP-1 activation in hepatic fibrosis of rat

BACKGROUND/AIMS

Intrahepatic renin-angiotensin-aldosterone system (RAAS) plays a key role in the fibrogenesis of liver. However, the signal transduction mechanism underlying effects of Angiotensin II (Ang II) and Aldosterone (Aldo) on Nuclear Factor-kappaB (NF-kappaB) and active protein-1 (AP-1) pathway in hepatic fibrogenesis remains to be fully elucidated. The present study aims to investigate the signal transduction mechanism underlying effects of Ang II and Aldo on NF-kappaB and AP-1 pathway during hepatic fibrogenesis.

METHODS

To assess the effect of AECI and Angiotensin II type 1 receptor (AT-1 receptor) blocker on NF-kappaB activity in liver, a model of fibrosis was performed in rat. In vitro, hepatic stellate cells (HSCs)-T6 cells were preincubated for 1 h or not with U0126, a specific inhibitor of extracellular signal regulated kinase (ERK), irbesartan, and N-acetylcysteine prior to exposure to Ang II or Aldo for the indicated times. DNA binding activity of NF-kappaB and AP-1 were analyzed by Electrophoretic mobility shift assay (EMSA). Western blot was used to detect expression of IkappaBalpha and Phospho-P42/44. RT-PCR was used to detect the expressions of tumor necrosis factor alpha (TNFalpha) mRNA and alpha1 (I) procollagen mRNA.

RESULTS

AECI and AT-1 receptor blocker exert anti-fibrosis effect through inhibiting NF-kappaB activation in liver. Ang II and Aldo increase HSCs NF-kappaB activity and NF-kappaB target gene-TNFalpha expression by inhibiting IkappaBalpha expression in a redox-sensitive manner. Ang II and Aldo also markedly increase HSCs AP-1 activity and AP-1 target gene-alpha1 (I) procollagen mRNA expression via ERK1/2 pathway in a redox-sensitive manner.

CONCLUSIONS

These results show that stimulation of NF-kappaB and AP-1 pathway mediate hepatic fibrogenesis induced by intrahepatic RAAS.